I can't believe this thread is still going on and on and on...

I don't recall anybody anywhere decreeing that anybody had a "right" to control the window shade on an airplane. If I recall correctly, they belong to the airline (or the leasing company), not to any of the passengers. Given this, I think the primary rule everybody should at least consider is that of courtesy. Otherwise, we're going to wind up with security guards on every plane to arbitrate disputes and prevent fisticuffs over window shade control.

In the spirit of Miss Manners, I hereby propose the following.

Rule 1: Everybody defers to whoever is in the middle seat. They have the worst seats in the plane (no decent view, no elbow room, no way to stretch legs, they have to ask to go to the washroom and they have to get up when the person in the window seat goes...).

Rule 2: Except for Rule 1, whoever has the window seat controls the window shade, the follwing apply in order:
a) if the pilot announces something visible off that side of the plane, it goes up;
b) except for (a), if the window seat occupant want it down, it stays down;
c) except for (a), if angle of the sun is such that anybody in the plane can't see the movie because of glare, it goes down;
d) except for (a, b, c), if the seatmates have a reasonable request for it to go down (they're sleeping, the glare from the sun makes their laptop look like a lightbox, they have vertigo, they're recovering from cataract surgery), it goes down;
e) if none of these apply, then the window shade goes up.

Rule 3: If the person closer to the window than you needs to go to the washroom, you must get up and let them, unless it is the window passenger who ignores Rule 2. However, you may not then complain about odd odors or dampness.